Solar trackers are used to rotate photovoltaic (PV) modules to keep them perpendicular to the direct rays of the sun. Keeping the array of PV modules at this orientation increases and ideally optimizes the amount of energy that can be generated by the array, because energy generated by a fixed tilt array drops off with the cosine of the angle of incidence of solar rays on the surface of each panel. Because tracker arrayscost more and have relatively low ground surface area utilization due to the required row-to-row spacing to prevent shading, trackers are typically used only in medium to large sized arrays (e.g., ≥1 megawatt). Although trackers add an additional cost per watt over fixed ground-mount systems, the cost is typically recouped on arrays of this size. Hardware and operating cost reductions will further expand the role of trackers in energy generation to even smaller sized arrays, that is ones below 1 megawatt.
In a single-axis tracker, photovoltaic modules are suspended above the ground in one or more horizontal rows, connected to a beam known as a torque tube. The torque tube, generally oriented along a North-South axis, is attached to a drive mechanism actuated by a controller to incrementally rotate the photovoltaic array in place over the course of the day to maintain a relatively constant angle with the sun as the sun progresses through the sky.
Some more sophisticated trackers known as dual-axis trackers not only rotate modules from East-to-West but also tilt modules towards the equator. With these trackers, modules are usually clustered together in individual sections, spaced apart from one another since they have to have greater spacing due to intra-row shading (shading of one section by an adjacent section in the same row), as well as inter-row shading (shading of one row by the adjacent row).
Because tracker arrays require very little post installation maintenance, the viability of these projects often turns on the projected rate of return derived from comparing the fixed value of the energy generated over the lifetime of the system versus the upfront costs of installation. In a multi-megawatt project, cost reductions of pennies per watt can be the difference between a project being viable or too expensive. Therefore, tracker designers are always seeking innovations to lower installation and hardware costs.
Accordingly, there remains a need for photovoltaic module assembly hardware that can make installation of solar tracker arrays more efficient and cost effective.